The present invention relates to an optical disk apparatus such as a portable CD player. In particular, the present invention belongs to a technology related to pull-in operation performed at an occurrence of a focus deviation.
FIG. 7 is a flowchart showing a conventional focus pull-in method, and FIG. 8 is a timing chart showing conventional focus operation. As shown in FIGS. 7 and 8, when a focus deviation is detected (YES in SZ1), a predetermined waiting time is first provided (SZ2) to wait for a spring supporting a lens of a pickup to stop vibrating, and then pull-in operation of jogging the pickup vertically at a fixed frequency is performed to search for a focusing point between the pickup and the disk (SZ3). A focus error is detected only near the focusing point. Therefore, detection of the focusing point is confirmed by generation of a focus error signal, and then servo operation is resumed. By operating in this way, focus pull-in is completed.
Problem to be Solved by the Invention
In recent years, manufacturers of portable CD players, for example, are active in development of joggable models free from skipping during jogging. Conventional portable CD players are equipped with a shockproof function of temporarily storing reproduced data. However, in a situation like jogging in which vibration is given at a fixed period, such a shockproof function will be of no use unless the time from a skip until recovery is sped up because a next skip will occur before reproduced data is stored, resulting in occurrence of an interruption.
Therefore, it is very important to perform focus pull-in swiftly once a focus deviation occurs, to ensure that new reproduced data can be stored before reproduced data stored in a memory is read out. In other words, one of requisites for implementing a joggable model is speeding up the focus pull-in.